FIG. 44 illustrates an example of a conventional image sensor module that may be utilized in an image reading apparatus (not shown). The image sensor module 901 illustrated in FIG. 44 includes a case 91, two light source units 92 and 93, a lens unit 94, and a sensor IC (Integrated Circuit) 95. The light source unit 92 is installed at a lower portion of the case 91 and includes a cold cathode fluorescent lamp (CCFL). The light source unit 93 is installed at an upper portion of the case 91 and includes an LED (Light Emitting Diode) chip. Above the case 91, a read target 890′ is transferred in a sub-scanning direction y. From the two light source units 92 and 93, linear lights extending along a main scanning direction are irradiated toward the read target 890′.
Positions of the two light source units 92 and 93 are substantially the same in the sub-scanning direction y, but different in a thickness direction z. Thus, incident angles of the linear lights from the two light source units 92 and 93 that reach the read target 890′ are different from each other. Reflected lights from the read target 890′ are collected on the sensor IC 95 via the lens unit 94. In a conventional image reading apparatus, which may include the image sensor module 901 for example, light emission timing of the light source units 92 and 93 are set to be different from each other, and thus the sensor IC 95 obtains data under different states, such as obtaining data under a state where the read target 890′ is irradiated only by the light source unit 92 and data under another state where the read target 890′ is irradiated only by the light source unit 93.
FIG. 45 illustrates another example of a conventional image sensor module. The image sensor module 902 illustrated in FIG. 45 includes a case 91, a lens unit 94, a sensor IC 95, a light source unit 96, a substrate 97, and a light transmission plate 98. The case 91 extends along the main scanning direction and accommodates therein or supports thereby the remaining elements. The light source unit 96 outputs linear lights extending along the main scanning direction toward the read target 890′. The lens unit 94 collects reflected light from the read target 890′ on the sensor IC 95. The sensor IC 95 is mounted on the substrate 97 and has a photoelectric conversion function.
In some cases, it is necessary to discriminate between different types of light, e.g., ultraviolet (UV) light versus visible light. In some cases, a filter, such as a UV filter may be used to prevent, a certain type of light from reaching the sensor IC 95. However, if a UV filter is used as the preventive measure, an appropriate UV filter installation space is necessary in the case 91 and the UV filter needs to be integrated such that it is prevented from being improperly deformed or distorted.
FIG. 46 illustrates a schematic block diagram showing an image sensor module in which a plurality of photoelectric conversion elements are divided into six blocks 910 to 960 to execute a reading operation. The image sensor module 903 illustrated in FIG. 46 includes a signal processing unit 970 installed on, e.g., a sheet of substrate. The signal processing unit 970 is configured to process signals from the six blocks 910 to 960. In the image sensor module 903, the reading operation is executed in parallel with respect to the six blocks 910 to 960, and the signal processing unit 970 converts analog output signals from the blocks 910 to 960 into digital signals and transmit the same to the controller 980.
According to the configuration of the image sensor module 903, lengthening a read width cannot be effectively achieved by adding more blocks. Since the signal processing unit 970 is configured to process signals from the six blocks 910 to 960, the signal processing unit 970 is required to be re-designed according to the new number of blocks. Therefore, such situations often cannot be effectively accommodated in conventional image sensor modules due the lack of flexibly of current functionality, and requires the specification of the image sensor module 903 to be modified, which would take a long time to development.
Therefore, there is a need for an image sensor module that is customized to address one or more of the limitations described above.